The present invention relates to a rubber composition for a sidewall or a clinch having improved cut resistance, crack growth resistance, and low fuel consumption of an automobile.
In order to improve cut resistance, crack growth resistance for a sidewall, a clinch of a tire, and low fuel consumption of an automobile, it is necessary to improve tan δ, hardness and stress and elongation (%) at break by tension for the rubber composition used for a sidewall and a clinch.
Conventionally, for the purpose of consuming low fuel in an automobile, a rubber composition for a sidewall employing a tin modified polybutadiene as a rubber component (see Japanese Unexamined Patent Publication No.5-320421) and a rubber composition for a sidewall employing a rubber composition containing crystal 1,2-syndiotactic polybutadiene as a rubber component (see Japanese Unexamined Patent Publication No.8-85303 and Japanese Unexamined Patent Publication No.10-110065) are disclosed.
However, there has been a problem that cut resistance and crack growth resistance are not sufficient in the technology described in Japanese Unexamined Patent Publication No.5-320421.
Also, there has been a problem that tan δ of the rubber composition was not decreased and sufficient low fuel consumption ability of an automobile in technology described in Japanese Unexamined Patent Publication No.8-85303 and Japanese Unexamined Patent Publication No.10-110065.